On 25/01/16 15:52, Arnd Bergmann wrote:
> The ade7753_spi_read_reg_16() will either successfully read a value
> from SPI, or return a failure code without delivering data. However,
> the ade7753_stop_device() and ade7753_reset() functions use the returned
> data without checking for an error condition first. Gcc detects this
> as a possible bug and warns about it:
>
> drivers/staging/iio/meter/ade7753.c: In function 'ade7753_remove':
> drivers/staging/iio/meter/ade7753.c:348:6: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> val |= BIT(4); /* AD converters can be turned off */
> ^
> drivers/staging/iio/meter/ade7753.c:345:6: note: 'val' was declared here
> u16 val;
> ^
> drivers/staging/iio/meter/ade7753.c: In function 'ade7753_probe':
> drivers/staging/iio/meter/ade7753.c:222:6: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>
> In both cases, we can avoids the warning by checking the return code
> before using the data.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Thanks.
Applied to the togreg branch of iio.git - initially pushed out as testing for
the autobuilders to play with it.
Thanks,
Jonathan
> ---
> drivers/staging/iio/meter/ade7753.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
> index f129039bece3..69287108f793 100644
> --- a/drivers/staging/iio/meter/ade7753.c
> +++ b/drivers/staging/iio/meter/ade7753.c
> @@ -217,8 +217,12 @@ error_ret:
> static int ade7753_reset(struct device *dev)
> {
> u16 val;
> + int ret;
> +
> + ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
> + if (ret)
> + return ret;
>
> - ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
> val |= BIT(6); /* Software Chip Reset */
>
> return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val);
> @@ -343,8 +347,12 @@ error_ret:
> static int ade7753_stop_device(struct device *dev)
> {
> u16 val;
> + int ret;
> +
> + ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
> + if (ret)
> + return ret;
>
> - ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
> val |= BIT(4); /* AD converters can be turned off */
>
> return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val);
>
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